Safety gate for vacuum packaging apparatus



W. F. PRENA 3,483,667

SAFETY GATE FOR VACUUM PACKAGING APPARATUS Filed July l1, 1967 Dec. E6, 1969 "llnited States Patent O 3,483,667 SAFETY GATE FOR VACUUM PACKAGING APPARATUS William F. Prena, Norridge, Ill., assignor, by mesne assignments, to .lohn Morrell & Co., Chicago, Ill., a

corporation of Delaware Filed July 11, 1967, Ser. No. 652,619 Int. Cl. B65b 57/14, 31/00, 5]/ 70 lU.S. Cl. 53-77 3 Claims ABSTRACT OF THE DISCLOSURE Vacuum packaging apparatus wherein a plurality of product carrying receptacles are movable along an endless conveyor to a sealing station where a layer of film is heat sealed to a receptacle as the air within the interior thereof is withdrawn, including a safety gate pivotally mounted on support structure adjacent the sealing station for actuating a switch connected in circuit with the cOnveyor driving motor to interrupt the circuit to the motor when an extraneous article is placed on the conveyor.

Background of the invention Summary of the invention The present invention provides an extremely simple, yet novel, means for detecting the presence of an extraneous article upon the conveyor of a vacuum packaging machine for actuating a switch means connected in circuit with the conveyor drive motor to stop the conveyor before the article is advanced into the sealing station.

Brief description of the drawings FIG. l is a side elevational view of a vacuum packaging machine including the safety gate structure of the invention;

FIG. 2 is an enlarged fragmentary side elevational view of the motor controlling switch structure and the actuator therefor; and

FIG. 3 is an enlarged view looking generally in the direction of the arrows 3-3 in FIG. l.

Detailed description of the preferred embodiment While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

The vacuum packaging machine of the present invention is similar in many respects to those disclosed in the above mentioned Myers and Prena applications, and the disclosures of these applications are hereby incorporated by reference in their entirety into this application.

Referring now to the drawings, a vacuum packaging machine is shown to include a frame having spaced "ice uprights 11 and supporting an elongate beam 12 with brace members 13 extending between uprights 11 at the lower ends thereof. A plurality of compartment defining trays or receptacles 14 are mounted on an endless conveyor defined by a plurality of pivotally interconnected links 15. The conveyor links 15 are trained over sprockets, such as shown at 16 at the rearward end of the machine, and the conveyor is driven from motor M by suitable drive means within housing 17. The drive means may take the form of that disclosed in the above mentioned Myers application, and such drive means is arranged to intermittently move the conveyor in a clockwise direction as viewed in FIG. l.

Spindle assemblies 17 and 18 are provided at the rearward and forward ends of the machine, respectively, and spindle assembly 17 is adapted to rotatably support and guide a first roll of film toward a film drawing station 19, while spindle assembly 18 is adapted to rotatably support and guide a second roll of film toward a sealing station 20. Film clamping members, not shown, are preferably provided at opposite sides of each tray 14 for clamping opposite edges of the film being fed from spindle assembly 17. Tuckers, either fixed or movable, are also preferably provided for tucking the edges of the film from spindle assembly 17 under the film clamping members. A heater 21 is provided at the film drawing station 19, and heater 21 heats the clamped film so that it is readily stretchable and can be drawn downwardly into the compartment within the tray 14 at the film drawing station 19. The film from spindle assembly 18 is sealed around the periphery of the film in tray 14 at the sealing station 20 as the interior of the thus formed package is evacuated by a sealing and evacuating head 22, which may take the form of the sealing and evacuating head disclosed in the above mentioned Myers application.

Article sensing means 24 is provided adjacent the path of movement of receptacles 14 immediately before the sealing station 20. The article sensing means includes a generally rectangular gate 25 fixed to a transversely extending shaft 26 by screws 27 or the like, Shaft 26 is mounted for rotation in frame members 28 and 29 at opposite sides of the path of movement of the receptacles 14, and for this purpose, frame mmebers 28 and 29 are provided with respective horizontally aligned openings 30 and 31 positioned above the path of movement of receptacles 14. The lower edge of the gate 25 is positioned so as to just clear the upper surface of receptacles 14 as they are advanced into the sealing station 20, so that any article that is left upon the receptacles will pivot gate 25 relative to the frame members 28 and 29.

Shaft 26 includes a portion 26a that extends laterally outwardly of frame member 29, and a switch actuator, in the form of a cam 33, is fixed on the shaft portion 26a. A switch 34 is mounted on frame member 29 in vertical alignment with cam 33, and switch 34 includes a movable plunger 35 for opening contacts within the switch that are connected in circuit with the conveyor drive motor M.

A spring mount, in the frame of an adjustable bolt 36, extends outwardly of cam 33, and a spring 37 is connected between bolt 36 and a lug 38 on frame member 29 to bias the shaft 26 in a clockwise direction (as viewed in FIG. 2) to position the bolt 36 in engagement with a stop 39 :arried by frame member 29. It will be understood that the spring 37 urges the gate 25 to a proper article sensing position with the lower end of the gate 25 being disposed immediately above the path of movement of receptacles 14 when the bolt 36 is positioned in engagement with stop 39. When the gate 25 is engaged by an article resting upon receptacles 14, the gate will be pivoted in a counterclockwise direction against the bias of spring 37, and the enlarged cam portion 33a at the lower end of the cam 33 will engage a roller 35a carried at the upper end of switch plunger 35 to depress the plunger, actuate the switch; and interrupt the circuit to motorM, thereby stopping the advancing movement of the receptacles 14 before the article on the receptacles can move into the sealing station.

In view of the fact that the sealing heads commonly used in vacuum packaging machines are complicated and expensive mechanisms, it will be appreciated that the simple, yet heretofore unobvious, expedient of providing a safety means for preventing damage to the sealing head is an extremely worthwhile innovation. Very often, during fabrication, initial installation, and servicing of vacuum pacakaging machines, it is common to place tools upon the receptacles 14, and the safety means of the present invention effectively prevents inadvertently placed tools from damaging the sealing head. Additionally, the safety gate means of the present invention prevents a workman, or an individual placing articles within the receptacles 14, from placing a hand within the sealing station, or in the rollers 40 which feed and guide lm from supply 18 to the sealing station.

I claim:

1. In a packaging apparatus wherein product carrying receptacles are advanced along a path toward a work station where closure means is applied to a receptacle, frame structure adjacent said work station including, frame members at opposite sides of said path having horizontally aligned openings therein above said path, motor driven means for advancing said receptacles to said work station, switch means carried by one of said frame members for deenergiz'ing the motor of said motor driven means to stop the advancing of said receptacles, and safety means positioned in said path before said work station for actuating said switch means upon engagement of said safety means by an extraneous article, said safety means comprising a gate carried by a shaft rotatably mounted in said openings for pivotal movement on said frame structure and having a switch actuator movable therewith and which is defined by a cam ixed to said shaft in vertical alignment with said switch means, the lower ends of said gate extending to a region immediately above said path so that extraneous articles left on said receptacles also will pivot said gate and actuate said switch, and spring means for biasing said gate toward an article sensing position.

2. Apparatus as set forth in claim 1 wherein said spring means is connected between said cam and said one frame member outwardly of said shaft.

3. Apparatus as set forth in claim 1 wherein an abutment is carried by said cam, and is engageable with a stop on said one frame member for properly locating the gate in an article sensing position.

References Cited UNITED STATES PATENTS TRAVIS S. MCGEHEE, Primary Examiner 

